ok now that tom-tom has finally been released (and the navigon sale extended), I have to the end of the month to decide if i will get tom tom, navigon, or neither. I'm sure plenty of reviews comparing the two are in the new future... but that's not what this thread is all about. Part of my concern is having a compassless iphone 3g. I assume the apps use the compass in the 3gs to even better the gps abilities by knowing precisely which direction you are facing. So I'm wondering exactly how well the 3g is able to do turn by turn, as opposed to the 3gs. If there is virtually no difference then I'll probably go ahead and get it now, but if the 3g is noticeably worse then the 3gs i could hypothetically wait till i get the 4th gen iphone next summer, because I'm not really in desperate need of gps at the moment. That would also allow me some time to read thru the reviews, grab any special tom tom deals that may happen within the next year, wait to see if map updates cost extra, or see if there is some other (better) gps is coming out. So does anyone know the difference the compass makes in a turn by turn gps app?